The Laryngoscope V C 2017 The American Laryngological, Rhinological and Otological Society, Inc. How I Do It Nasoseptal Flap Closure of the Eustachian Tube for Recalcitrant Cerebrospinal Fluid Rhinorrhea Vishal S. Patel, BS ; Garret W. Choby, MD; Andrew Thamboo, MD, MHSc; Nikolas H. Blevins, MD; Peter H. Hwang, MD INTRODUCTION Recalcitrant cerebrospinal fluid (CSF) rhinorrhea after vestibular schwannoma surgery can be a challenging com- plication. 1–6 CSF rhinorrhea can occur following retrosig- moid, middle fossa, or translabyrinthine approaches with approximately equal frequency, and represents a dural breach of CSF transmitted via the eustachian tube (ET) to the nasal cavity. Many postoperative CSF leaks can be suc- cessfully managed with conservative measures, such as bedrest and lumbar drain placement. However, as many as 41% ultimately require surgical intervention. 7 In the absence of serviceable residual hearing, the first-line surgi- cal approach typically involves transotic external auditory canal (EAC), middle ear, and ET obliteration with fat, mus- cle, and/or bone wax. Second-line treatment for refractory cases may include additional mastoid obliteration or ventri- culoperitoneal (VP) shunt placement. 8 For intractable cases of CSF rhinorrhea, endoscopic transnasal techniques for ET closure have also been introduced, including cauterization of the ET orifice, suture closure, closure with acellular der- mal matrices, or combinations thereof. 9–11 However, these methods have proven to have variable levels of success. The pedicled nasoseptal flap (NSF) was first described in 2006 for closure of anterior skull base defects. 12 Based on the posterior septal branch of the sphenopalatine artery, the NSF offers significant advantages over traditional free graft techniques, including preserved vascularity, a broad ana- tomic reach, and a large potential area of coverage. The NSF has become the workhorse reconstructive technique for repair of skull base defects in endoscopic anterior skull base surgery, decreasing postoperative CSF leak rates from greater than 20% to less than 5%. 11–14 Here, we describe the application of the NSF for endoscopic endonasal closure of the ET for recalcitrant CSF rhinorrhea following lateral skull base surgery for vestibular schwannoma. MATERIALS AND METHODS Two patients with persistent CSF rhinorrhea after retro- sigmoid resection of a vestibular schwannoma were offered an endonasal closure of the ET using an ipsilateral NSF. Case 1 Patient 1 was a 59-year-old woman who underwent a ret- rosigmoid approach for resection of a 3.2-cm left vestibular schwannoma. She had intermittent CSF rhinorrhea for 2 weeks despite conservative measures including lumbar drain place- ment. She subsequently underwent middle ear obliteration and transotic closure of the ET with temporalis muscle. She had temporary resolution of symptoms, but 3 months later had recurrent symptoms of CSF rhinorrhea. A VP shunt was then placed 4 months postoperatively. Despite optimal control of CSF pressures, the patient continued to leak intermittently and was then referred to our clinic 7 months postoperatively. Case 2 Patient 2 was a 64-year-old woman with a 4.0-cm right vestibular schwannoma who developed CSF rhinorrhea 1 week after undergoing a retrosigmoid approach for resection. Despite conservative measures, she continued to leak, and at 1 month postoperatively she underwent EAC closure, middle ear obliter- ation, and transotic ET closure with bone wax and temporalis muscle plug. Although she had temporary resolution of symp- toms, she presented with a relapse of CSF rhinorrhea 6 months later, and underwent revision ET and middle ear obliteration with bone wax and temporalis muscle grafting. One year later, she again had recurrent CSF rhinorrhea and underwent place- ment of a VP shunt. Despite a functional shunt, she had contin- ued CSF leakage and was referred to our clinic. Surgical Technique Step 1: raising the NSF. Prior to raising the NSF, the ET opening was first identified with CSF leaking from its From the Department of Otolaryngology–Head and Neck Surgery (V .S.P ., G.W.C., A.T., N.H.B., P .H.H.), Stanford University School of Medicine, Stanford, California, U.S.A.; Department of Otorhinolaryngology (G.W.C.), Mayo Clinic, Rochester, Minnesota, U.S.A.; and the Department of Otolaryngology–Head and Neck Surgery (A.T.), University of British Columbia, Vancouver, British Columbia, Canada. Editor’s Note: This Manuscript was accepted for publication October 5, 2017. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Peter Hwang, MD, Department of Otolaryn- gology–Head and Neck Surgery, Stanford University School of Medicine, 801 Welch Road, Stanford, CA 94305. Email: hwangph@stanford.edu DOI: 10.1002/lary.26988 Laryngoscope 00: Month 2017 Patel et al.: Nasoseptal Flap Closure of the ET 1